Conventionally, as one of substrate cleaning apparatuses of processing a substrate such as a semiconductor wafer, there is known a substrate cleaning apparatus configured to clean the substrate by bringing the brush into contact with the substrate and rotating the brush with respect to the substrate while supplying a processing liquid to the brush from the outside of the brush (Patent Document 1).
Patent Document 1: Japanese Patent No. 4,685,914
If, however, different kinds of cleaning liquids are supplied to the brush, there may be a problem such as generation of a salt caused by a reaction between plural chemical liquids supplied one after another. In the prior art, however, a solution to such a problem is yet to be considered.